The present invention relates generally to imaging sensors, and more specifically, to imaging sensor module assemblies for digital imaging applications.
Imaging devices are used to capture still and video images which then can be transformed into analog or digital formats. For example, imaging devices are commonly used in digital cameras, personal computer cameras and other imaging applications. The primary components of an imaging device are an optical lens, a lens housing, an imaging sensor and a printed circuit board. The optical lens receives and focuses light from the environment to be captured onto the imaging sensor. The lens housing is critical for securely positioning the lens over the imaging sensor so that the captured light may be properly focused onto the imaging sensor. The imaging sensor is connected to a printed circuit board in order to be electrically connected to the rest of the imaging system.
The current method of assembling an imaging device generally involves attaching the lens housing and the imaging sensor directly to the printed circuit board. The optical lens is inserted into the lens housing after these components are attached. Examples of current imaging device assemblies are illustrated in FIGS. 1 and 2. In FIG. 1 an optical lens 10, which is secured by an interior lens housing 11, is positioned over an imaging sensor 14 by an external lens housing 12. Both the imaging sensor 14 and the external lens housing 12 are attached to a printed circuit board 16. The imaging sensor 14 is connected to the printed circuit board 16 by solder ball electrical contacts 15 and has optical sensors on its top surface. The exemplary assembly illustrated in FIG. 2 is similar to that shown in FIG. 1 except for a few variations. First, a plate of glass 20 is attached to the external lens housing 12 in order to protect the imaging sensor 14 from dust particles, moisture, etc. Also, the imaging sensor 14 is connected to the printed circuit board by wire bond interconnects 17, rather than by solder ball electrical contacts 15 (see FIG. 1).
Unfortunately, there are various aspects of the current imaging device assembly that are undesirable. The first aspect involves the assembly steps which must be subject to rigorous process controls to ensure that the lens is centered, leveled and placed at a proper distance with respect to the imaging sensor. Implementation of these process controls adds complexity, time and costs to the assembly process. Secondly, the numerous components making up the imaging device reduces the ability to have components created in standard sizes and forms so that future designs and implementations may be created more simply. Finally, because a large area is occupied when a lens housing is attached to the printed circuit board, it is difficult to design smaller devices in accord with the constant desire in the electronics industry for miniaturization.
In view of the foregoing concerns, an improved concept for components which may be assembled into an imaging device would be desirable. Such components and their assembly should allow for faster and easier assembly, modularity and standardization of the components, and facilitate design requirements aimed at miniaturizing imaging devices.
The present invention is directed to an imaging sensor module assembly adapted to be mounted to a substrate for use in electronic imaging devices. The module assembly includes an optical lens, and a sensor package having a sensor surface containing an optical detector portion. The sensor further includes a plurality of sensor contacts in electrical communication with the optical detector portion. A flex circuit includes a plurality of circuits terminating at respective terminals electrically coupled to a corresponding sensor contact. The module assembly further includes a lens housing assembly configured to support the optical lens, and a barrel portion adapted to fixedly couple to the sensor package. This coupling orients the lens a predetermined focal length from the sensor package such that light waves passing through the lens are focused onto the optical detector portion.
In one embodiment, the sensor contacts, which could be solder bumps, of the sensor package are positioned on the sensor surface, generally adjacent the detector portion. The flex circuit is thus mounted to the top side and connected to the contacts.
In another configuration, the housing assembly includes support housing adapted to couple to the barrel portion thereof. The housing assembly defines a cavity formed for aligned receipt of the sensor package therein at an aligned orientation positioning the optical detector portion the sensor package at the predetermined focal length from lens such that light waves passing through the lens are focused onto the optical detector portion. The support housing includes a support surface defining an access opening into the cavity. The support surface is adapted to support the barrel portion thereon such that the light waves pass through the port and onto the sensor package detector portion.
In one arrangement, the support housing includes alignment walls defining an alignment slot portion of the cavity. When the sensor device is received in the slot portion, the alignment walls cooperate with the sensor device to receivably align the optical detector portion thereof with the lens.